Lifting jack



Sept. 19, 1933. w T, WALKER 1,927,326

LIFTING JACK Original Filed Nov. 19, 1930 Patented Sept. 19, 1933 UNITED STA mmc .mex

Willard T. Walker, Racine, Wis., assignor to Walker Manufacturing Company, Racine, Wis., a corporation of Wisconsin Original application November 19, 1930, Serial No. 496,696, now Patent No. 1,914,149, June 13, 1933. Divided and this application May 1 1933. Serial No. 670,904

- 7 Claims. (Cl. 25498) TES PATENT OFFICE This invention relates to certain new and useful improvements in lifting jacks, and more particularly to limprovements in a jack of the screw type comprising a stamped metal casing or standard having spring means mounted in the standard for yieldably controlling 'the rotation of the lifting screw.

Briefly described, the jack'comprises a pressed metal standard creasing consisting of formed sections which when iltted together support-and o will be more apparent from the following detail;l description of certain approved forms of apparaalmost completely house the moving parts of the jack mechanism. The standard encloses a vertical cylindrical guidepassage for a lifting screw, and one of the standard sections is formedwith a vertically extending hollow rib which not only strengthens the standard section but provides an enclosed vertical slot extending outwardly from the guide'passage. In this slot' is supported a leaf spring so formed that a portion thereof will project into the guide passage and frictionally engage the lifting screw so as to tend to prevent rotation thereof and cause the screw to move vertically when the driving nut through which the screw is threaded is rotated. The invention tus constructed .and operating according to the principles of this invention.

This invention was ilrst disclosed in the copendingv application of Mizer, Sullivan and Walker, Serial No. 496,696, filed November 19, 1930, patented June 13, 1933 as Patent No. 1,914,149 of which pending application this present application is a division.

In the accompanying drawing:

Fig. 1 is an elevation of one of the assembled jacks.

Fig. 2 is a central vertical section through the jack, the view being taken substantially on the line 2 2 of Fig. 3.-

Fig. 3l is a horizontal section through the jack taken substantially on the line 3-3 of Fig. 2.

Fig. 4 is a central vertical section through the jack, parts being broken away, this view being taken at right angles to the view shown in Fig.

2, or substantially on the line 4--4 of Fig. 2.

Fig. 5 is a partial vertical section, similar to Fig. 4, but showing a modification.

The movable parts of the jack comprise a vertical lifting screw 1, at the top of which is a 05 cap or rest 2 for supporting the load to be lifted. Lifting screw 1 is threaded through and supported by a nut 3, which in 'turn is supported on a ball-bearing assembly comprising upper and lower raceways 4 and 5 between which is a 70 circular series of ball bearings 6 carried by a cage '1. A short, laterally projecting operating shaft 8 is provided with a socketedhead 9 at its outer end whereby connection is made with a removable operating handle, and a bevel pinion 10 formed at the inner end of shaft 8 meshes with a beveled gear 11 formed on the nut 3. It will -now be seen that if the operating shaft 8 is rotated, the nut 3 will be rotated about the vertical axis of lifting screw 1, and-1f the 80 lifting screw is held from rotation (as it will be when engaged with the load), the lifting screw and the load carried thereby will be elevated or lowered, depending upon the direction of rotation of operating shaft 8 and nut 3.

'Ihe improved sheet metal housing for supporting and enclosing the movable elements of the jack comprises, in the embodiment here shown, a base plate 12 and a pair of similar upright standard sections 13 and 14. The base plate is preferably formed of a single piece of stamped or pressed sheet metal which is strengthen d by means of upright side flanges l5 and ribs zontal main portion of the plate.

Each section 13 and 14 of the upright standard is formed to enclose substantially half of an upper disk-like chamber 1'7 which houses the operating gears and nut and the roller bearings, alaterally projecting bearing chamber 18 in which operating shaft 8 is journaled, and a vertically extending cylindrical chamber 19 which or pockets 16 stamped into the substantially hori- 95 serves as ahousing and guide for the lifting screw 1. Each standard section 13 and 14 is provided with a laterally extending side flange 20, which extends substantially radially from the central vertical axis of the jack, and which projects from all of the side and upper portions of the standard member except at the outer end' of the bearing 18 for the operating shaft s. 11

At the top of the housing sections, this flange 20 extends as part of a vertical cylindrical collar 21 which surrounds the opening through which the lifting screw 1 projects. Each standard section is preferably provided with a vertically extending hollow rib 22 which is centered in a plane substantially perpendicular to the plane of the side flanges 20. This rib may extend from the upper chamber 17 to the lower end of the standard section and serves to brace and stiifen the jack housing, while at the same time providing an internal vertical slot 23. The controlling spring hereinafter described is mounted and housed within one of these slots 23. The lower end portions' 24 of the side flanges 20, and the lower portions 25 of the ribs 22 all flare Aoutwardly so as to provide a broader supportingx base for the standard crease its strength.

In order to assemble this jack, the several movable elements of the jack are first assembled as shown for example in Fig. 2 and placed within one of the standard sections, and the two standard sections 13 and 14 are then assembled together about the movable elements by securing the side fianges 20 together in any suitable manner. These side flanges may be spot welded and additionally inor riveted to one another, and in the example here shown the side flanges 20 of one of the sections (for example the section 14) are pro- -vided with extensions 26 which are folded over and clamped against the outer sides of the flanges 20 of the other member 13 so as to bind the two housing sections firmly together. The lower end portions of the upright standard sections are secured to the base plate 12 in any suitable manner, preferably by providing outwardly extending flanges (not here shown) on the lower ends of the standard sections which are riveted or otherwise secured to the base plate. Before the housing is entirely assembled it may be packed with grease so as tc assist the operation of the moving parts and keep them in proper condition. The completed jack will be painted or enameled thus sealing all of the joints, and the only openings remaining in the casing are the upper passage through which the lifting screw reciprocates and the lateral passage 18 in which the operating shaft 8 is journaled. 'I'hus there will be very little escape of grease and the operating parts will be protected against oxidation and maintained in proper working condition for an indefinite time.

The improved jack assembly, as thus far described, is disclosed somewhat more in detail and claimed in the copending application of Mizer, Sullivan and Walker, Serial No. 496,696, hereinabove referred to.

The present invention relates more particularly to improved means, adapted to be mounted in a pressed metal casing of thistype, for controlling the rotation of the lifting screw 1. It will be apparent that if the screw 1 is free to rotate, it will simply rotate with the driving nut v3 and will be neither raised or lowered when the shaft 8 and nut 3 are rotated, unless the lifting cap 2. is in engagement with the load so as to prevent rotation of the screw. It is desirable that the rotation of screw 1 be prevented at other times so that the screw may be lifted into engagement with the load, or completely lowered when moved out of engagement with the load, all by rotation of the operating shaft 8. In the form of jack disclosed in the parent application hereinabove referred to, a key or projection is tically through' the ,it may be turned by hand, in opposition to this yieldable means, to raise or lower the screw without rotation of the operating shaft. Also in multiple screw jacks, as now well known in this art, it is desirable that the outer lifting screw be permitted to rotate when moved to ether its upper or lower limit of travel so as to cause further movement of an inner lifting screw. In order to accomplish these purposes, it has been proposed to provide a spring means frictionally engaging the outer surface of the threads on the lifting screw. The frictional resistance thus provided is sufficient to prevent-rotation of the screw and cause it to be moved vertically through the driving nut when the nut is rotated. The present inventori relates to an improved form of spring means for accomplishing this function, said spring means being simple and eflicient and particularly adapted for use in a pressed metal standard of the type hereinabove described.

Referring first to the form-shown in Fig. 4, a small leaf spring 27 is positioned within the upper portion of the slot 23 provided in rib 22 of one of the standard sections, for example the standard section 14. This spring is secured at one end to the standard section by means of a rivet 28 or other suitable securing means, and the spring is bowed or curved so as to provide a portion 29 which projects inwardly from slot 23 into the guide passage 19 so as to frictionally bear against the outer surfaces of the threads on the lifting screw 1. The upper end of the spring maa,1 again be bowed outwardly as at 30 so that this end will bear against the bottom of the slot 23 and additionally stiffen the spring.

In the modified form shown in Fig. 5, a lip 31 Ais struck inwardly from the outer wall of ,the and the lower end` and also against the lower face of the race ring 5 so as to holdthe spring in position.

This spring (27 or 33) exerts a continuous yielding pressure on the outer surface of the lifting screw, and the yielding resistance to rotation offered by the spring is sufficient to overcome the tendency of the screw 1 to rotate with the nut 3 when there isno load on the lifting screw, and consequently the lifting screw will be moved vernut when the nut is rotated. It will be apparent that this improved form of spring means is quite simple and inexpensive, and may be mounted within v one of the strengthening ribs 22 provided ina sheet metal standard of this type without requring any additional modifications of the Jack housing. This form of holding means permits the screw to be run quickly in or out by hand to approximately the initial postion desired before placing the Jack beneath the load. It is also adapted for use in jacks of the multiple screw type, in which no change is necessary other than the addition of an auxiliary or inner lifting screw threaded within the outer screw 1, as is well known in this art,

I claim: 1. In combination with the moving parts of a lifting jack comprising a vertically moving lifting screw, a nut through which the screw is threaded, and means for rotating the nut, a' standard for supporting the moving parts, said standard comprising sheet metal standard s'ections secured together and so formed as to enclose a central vertical guide passage for the lifting screw, one of the sections being formed with a vertically extending hollow rib enclosing a slot which opens inwardly into the guide passage, and means for exerting a frictional drag on the screw to prevent rotation thereof, said means comprising a leaf spring positioned within the slot and having one end portion secured to the standard section within the rib', the spring being so formed that a portion thereof will project into the guide passage and bear frictionally against the threaded surface of the screw.

2. In combination with the moving parts of a lifting jack comprising a vertically moving lifting screw, a nut through which the screw is threaded, and means for rotating the nut, a standard for supporting the moving parts, said standard comprising sheet metal standard sections secured together and so formed as to enclose a central vertical guide passage for the lifting screw, one of the sectionsbeing formed with a vertically extending hollow rib enclosing a slot which opens inwardly into the guide passage, and means for exerting a frictional drag on the screw to prevent rotation thereof, said means comprising a bowed leaf spring positioned within the slot and having one end portion secured to the standardsection within the rib, the inwardly bowed portion of the spring projecting into the guide passage so as to engage frictionally against the threaded surface of the screw.

3. In combination with the moving parts of a lifting jack comprising a vertically moving lifting screw, a nut through which the screw is threaded, and means for rotating the nut, a standard for supporting the moving parts, said standard comprising sheet metal standard sections secured together and so formed as to enclose a central vertical guide passage for the lifting screw, one of the sections being formed with a vertically extending hollow rib enclosing a slot which opens inwardly into the guide passage, and means for exerting a frictional drag on the screw to prevent rotation thereof, said means comprising a bowed leaf spring positioned within the slot and having one end portion riveted to the standard section within the rib, the inwardly bowed portion of the spring projecting into the guide passage so as to engage frictionally against the threaded surface of the screw.

4. In combination with the moving parts of a `lifting jack comprising a vertically moving lifting screw, a nut through which the screw is threaded, and means for rotating the nut, a standard for supporting the moving parts, said standard comprising sheet metal standard sections secured together and so formed as to enclose a central vertical guide passage for the lifting screw, one of the sections being formed with a vertically extending hollow rib enclosing a slot which opens inwardly into the guide passage, and means for exerting a frictional drag on the screw to prevent rotation thereof, said means comprising a bowed leaf spring positioned within the slot and having one end portion secured to the standard section within the rib and the other end portion engaging the standard within the rim, the inwardly bowed portion of the spring projecting into the guide passage so as to engage frictionally against the threaded surface of the screw.

5. In combination with the moving parts of a lifting jack comprising a vertically moving lifting screw, a nut through which the screw is threaded, and means for rotating the nut, a standard for supporting the moving parts, said 'standard comprising sheet metal standard sections secured together and so formed as to enclose a central vertical guide passage for the lifting screw, one of the sections being formed with a vertically extending hollow rib enclosing a slot which opens inwardly into the guide passage, and means for exerting a frictional drag on the screw to prevent rotation thereof, said means comprising a bowed leaf spring positioned within the slot with the inwardly bowed portion of the spring projecting into the guide passage to engage frictionally against the threaded surface of the screw, there being a lip struck inwardly from the outer wall of the rib to engage one end of the spring and hold it in position.

6. In combination with a section of a sheet metal lifting jack housing, said section being formed with a portion of a cylindrical guide passage for a lifting screw and also formed with a 4hollow rib extending parallel to the passage and enclosing a longitudinally extending recess communicating with the passage, a leaf spring positioned within the recess so that a portion thereof 'will project yieldably into the passage to engage the screw and means for securing one endof the spring to the standard section within thev recess.

7. In combination with a section of a sheet metal lifting jack housing, said section being formed with a portion of a cylindrical guide passage for a lifting screw and also formed with a hollow rib extending parallel to the passage and enclosing a longitudinally extending recess communicating with the passage, a leaf spring positioned within the recess so that a portion thereof will project yieldably into the passage to engage the screw and a rivet securing one end portion of the spring to the outer wall of the rib within the recess.

WILLARD I. WALKER. 

